Some memory structures (e.g., dynamic random access memory (DRAM), electrically erasable programmable read-only memory (EEPROM), flash memory, etc.) are commonly arranged in arrays of memory cells. During a read operation, one or more of the memory cells are selected and activated. For example, the selected memory cells are enabled and are electronically connected to sense amplifiers, which can distinguish signals from the memory cell that represent a stored 0 or 1. The sense amplifier can then provide the sensed value to an output.
A sense amplifier can also precharge a bitline to a proper voltage level in a read operation. After the precharge operation, the sense amplifier uses the precharge voltage to sense a selected memory cell current flowing through the bitline. For example, the sense amplifier can compare the memory cell current with a current threshold. If the memory cell current is greater than the current threshold, then the stored bit can be, for example, a logic 0. If the memory cell current is less than the current threshold, then the stored bit can be, for example, a logic 1.
Some sense amplifiers have a current threshold (Icellth) that is uncorrelated with the operational characteristics of a selected memory cell. A mismatch between Icellth and a memory cell current can degrade the precision of a sense amplifier.